from typing import *


class TreeNode:
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None

class Codec:

    def serialize(self, root: Optional[TreeNode]) -> str:
        """Encodes a tree to a single string.
        """
        

    def deserialize(self, data: str) -> Optional[TreeNode]:
        """Decodes your encoded data to tree.
        """